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THE MOHR DIAGRAM AND COULOMB EQUATION

REFERENCE IS MADE TO THE CURRENT DIFFERENCE OF OPINION THAT APPEARS TO EXIST CONCERNING THE SIGNIFICANCE OF THE COULOMB EQUATION, THE MOHR DIAGRAM, AND THE RELATIONSHIP BETWEEN THEM. THE PAPER REVIEWS THE SIMPLEST CASE, THE STRESSING OF CERTAIN SOILS OR SIMILAR MATERIALS FOR WHICH THE COULOMB, PRINCIPAL STRESS, AND MOHR ENVELOPES ARE STRAIGHT LINES. TWO PRINCIPAL CONCLUSIONS ARE PRESENTED. THE COULOMB ENVELOPE RESULTING FROM DIRECT SHEAR TEST DATA, AND THE MOHR ENVELOPE OBTAINED FROM TRIAXIAL DATA WILL BE IDENTICAL FOR A GIVEN MATERIAL, PROVIDED THAT IDENTICAL SAMPLES OF THE MATERIAL ARE SUBJECTED TO IDENTICAL CONDITIONS DURING BOTH TESTS. THEORIES OF STABILITY FOR THESE MATERIALS THAT ARE BASED EXCLUSIVELY ON EITHER THE PRINCIPAL STRESSES, OR ON RELATIONSHIPS BETWEEN NORMAL STRESS, SHEARING STRESS, AND SHEARING RESISTANCE, OR ON THE ANGLE OF INTERNAL FRICTION, OR ON THE ANGLES BETWEEN THE PLANE OF FAILURE AND THE MAJOR OR MINOR PRINCIPAL PLANES, OR ON COMBINATIONS OF TWO OR MORE OF THESE, ARE ACTUALLY SUPPLEMENTARY THEORIES THAT PROVIDE IDENTICAL SOLUTIONS TO ANY STABILITY PROBLEM CONCERNING THESE MATERIALS. BECAUSE OF THE INCREASING INTEREST IN THE USE OF THE TRIAXIAL TEST FOR THE SOLUTION OF HIGHWAY AND AIRPORT ENGINEERING PROBLEMS, IT IS IMPORTANT THAT AGREEMENT SHOULD BE REACHED REGARDING THE SIGNIFICANCE OF THE MOHR DIAGRAM FOR THE ANALYSIS OF TRIAXIAL DATA, AND CONCERNING THE NATURE OF THE RELATIONSHIP BETWEEN THE COULOMB AND MOHR DIAGRAMS. /AUTHOR/

Supplemental Notes:

Vol 30, pp 435-449, 12 FIG, 9 REF

Authors:

Mcleod, N W

Publication Date: 1951

Media Info

Monograph Title: Proceedings of the Thirtieth Annual Meeting of the Highway Research Board Held at Washington, D.C., January 9-12, 1951